Conventionally, for example, as shown in JP-A Publication No. 08-200905 as below, at a site where an air conditioner is installed, an operation to charge refrigerant according to the capacity of each installed equipment is performed before adjusting the air conditioner through the test operation. In this air conditioner, the refrigerant quantity to be additionally charged is automatically calculated and displayed by using information on the diameter, length, and the like of a pipe that is used for connection. In addition, such refrigerant charging is performed not only at the time of installation as described above but also at the time of re-charging in case of a refrigerant leak, re-charging after troubleshooting, and the like.